config OpenMP: check for C++ flag any time the compiler is available

Otherwise C++ source files such as matelem.cxx are compiled without the
-fopenmp flag, which causes breakage due to non-TLS variables when using
threads.
config cmakeboot: add C++ flags any time compiler is available

Otherwise C++ files like matelem.cxx would not be compiled with
appropriate flags when clanguage=C.
parmetis: update tarball to parmetis-4.0.2-p5 which fixes an install issue with cygwin
parms: update tarball with fix for namespace conflict with metis
Merge branch 'jed/config-openmp-cxx' into maint

* jed/config-openmp-cxx:
  config cmakeboot: add C++ flags any time compiler is available
  config OpenMP: check for C++ flag any time the compiler is available
VTK: Small fix to error message (.vts to .vtu)

(cherry picked from commit 3da621eca82108b806df3de7cc9ccd7d23a76f9c)

Conflicts:
	src/sys/classes/viewer/impls/vtk/vtkv.c